AD9804AJST

Overview

The AD9804AJST is a complete analog signal processor for CCD applications, featuring an 18 MHz single-channel architecture designed to sample and condition outputs of interlaced and progressive scan area CCD arrays. The device integrates an input clamp, correlated double sampler (CDS), digitally controlled variable gain amplifier (VGA) with a range of 6 dB to 40 dB, black level clamp, and a 10-bit A/D converter. It operates on a single 3 V supply with low power consumption of 85 mW. The internal VGA gain register is programmable via a 3-wire serial digital interface. The component is housed in a 48-lead LQFP package and supports an operating temperature range from -20°C to +85°C.

Feature Summary

• Integrates a 10-bit, 18 MSPS analog-to-digital converter within a single-channel architecture.
• Includes a digitally controlled variable gain amplifier providing a gain range from 6 dB to 40 dB.
• Features low noise clamp circuits and a preblanking function for signal conditioning.
• Utilizes a 3-wire serial digital interface for programming the internal VGA gain register.

Applications

• PC Cameras
• Digital Still Cameras

Procurement Notes

Verify the specific ordering suffix AJST corresponds to the Thin Plastic ST-48 Quad Flatpack (LQFP) package with an operating temperature range of -20°C to +85°C. Confirm that the component status is obsolete before initiating procurement processes, as availability may be limited or restricted to secondary markets.

Selection Notes

Select this component for applications requiring a complete analog front-end solution for CCD image sensors. Ensure the system timing generator can provide the necessary SHP, SHD, and DATACLK signals at frequencies up to 18 MHz. Verify that the host ASIC or microprocessor supports the required 3-wire serial interface protocol for register configuration.

Part Context

The AD9804AJST belongs to the AD9804 family of CCD signal processors manufactured by Analog Devices Inc. This series provides integrated signal conditioning and digitization for CCD arrays. The AJST suffix specifically denotes the 48-lead LQFP package variant suitable for surface-mount assembly in consumer imaging electronics.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. The datasheet lists similar parts such as the AD9806, AD9840A, and AD9843A, but these have different sampling rates and pin configurations, requiring careful evaluation of compatibility.

FAQ

What is the maximum clock rate supported by the AD9804?

The maximum clock rate supported by the AD9804 is 18 MHz.

How is the VGA gain programmed?

The internal VGA gain register is programmed through a 3-wire serial digital interface using SCK, SDATA, and SL pins.

What is the power consumption of the AD9804?

The power consumption of the AD9804 is 85 mW when operating under standard conditions.